/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Spring.Util.Generic;

namespace Spring.Dao.Support.Generic;

/// <summary>
/// Miscellaneous utility methods for DAO implementations.
/// Useful with any data access technology.
/// </summary>
/// <author>Mark Pollack (.NET)</author>
public class DataAccessUtils
{
    /// <summary>
    /// Initializes a new instance of the <see cref="DataAccessUtils"/> class.
    /// </summary>
    public DataAccessUtils()
    {
    }

    public static T RequiredUniqueResultSet<T>(IList<T> results)
    {
        int size = (results != null ? results.Count : 0);
        if (size == 0)
        {
            throw new EmptyResultDataAccessException(1);
        }

        if (!CollectionUtils.HasUniqueObject(results))
        {
            throw new IncorrectResultSizeDataAccessException(1, size);
        }

        IEnumerator<T> enumerator = results.GetEnumerator();
        enumerator.MoveNext();
        return enumerator.Current;
    }
}
